To provide the display unit which can display arbitrary data representing the state of operation in an arbitrary PLC(programmable controller) through easy operation even when the PLC is connected.

The display unit 1a is connected to the programmable controller 8 and displays pieces of data representing the state of the operation of the programmable controller 8 with information assigned to respective codes indicating the locations of the data. The display unit is equipped with a storage means 5 which stores the code indicating the location of the data representing the state of the operation of the connected programmable controller 8 and name information assigned to the code so that they correspond to each other and a means 2 which displays the mentioned data with the name information stored in the storage means 5.